I'm currently repairing my old board but I'm stuck at hot coating, or at least I believe I'm hot coating...

I'm using off-the-shelf sun-curing resin kit to fill dings, sand it to the board contour, then a layer of fibreglass. Sand it down again and I put a thin coat of the same resin to fill any bubbles and even the surface. BUT the coating doesn't dry completely...

The resin isn't dripping but a light touch and I get a fingerprint on the surface...not dry enough to wet sand it. Been outside for 30min and still not drying. The resin hardened in less than 10min when I filled the dings, but a thin coat of the same resin doesn't cure even after half hour.

Is it proper sun cure resin?Problems may beIf you have used the resin before and not turned the bottle upside down a few times before use,you may have poured all the wax out of the bottle the first time you used it as it floats to the top of the bottle.No wax left in the bottle will make the resin hard but very tacky.

If that's not the problem did you let the board stand for 5 mins before exposing to uv to let the wax rise to the surface? If you shoved it straight out into the sun the wax will be still trapped in the resin and it would never fully cure and be soft.

Are you making sure that the part of the board you have applied resin to is facing upwards when exposing to sun light to let the wax rise.

Best thing to do with uv resin is to put the resin on the board and let it stand with the damage facing upwards for five mins then stick it outside for 15 seconds. Back inside for a minute or two then back out in the sun until its fully cured.

It's Phix Doctor kit and the resin is in one of those Capri-Sun type of container. I didn't think of shaking/mixing the resin well before pouring it out. AND I stuck it outside as soon as I finished coating the area with a brush. I always make sure that the resin is exposed directly to the UV ray.

I'm convinced with your wax assumption. I don't remember how it came out the first time I opened the container, but the coat I did is definitely harder than earlier but still sticky to touch. argh.

Lesson learned. Mix well before use, let it settle before UV exposure, 15sec exposure, 1-2min in shade, and full whack until cured.

I glassed a board in the middle of winter a few years back, something I won't be doing again. Annoying as fuck, as I did the board in 10oz volan. Took my time, top of the board was flawless. Bottom, (done a week later during a temp drop) wasn't. Thought it was fine, went back in the day after to sand it and it was coming away in clumps.

Just stick another layer over the tacky resin and once cured it will make the stuff that's already on the board sandable.Resin will cure tacky and be un sand able if it is exposed to air while curing. The wax forms a barrier when it floats to the top of the resin but you just got to give it time to rise before,exposing to the sun.If you say put resin onto a whole rail then stick the board in the sun laying flat,the top side of the rail will cure ok but the bottom side of the rail will cure tacky and fall off the board because the wax will rise against the board not to the surface of the resin. So once the resin is on the rail always keep the rail facing upwards even when carrying it outside and all should be good.

Nightmare indeed... But it's okay because it's an old board so I'm happy as long as it's water tight. A good hot coat would've been a bonus so just learning on it.

Thanks Coxie for your advice. What I'm bit confused is that I did exactly the same with using the same resin to fill a ding and it was perfectly fine. Rock hard in less than 10min under the cloud. But same procedure on hot coat and I got a mess. May be when I brushed the coating (cheap B&Q 75p brush...), would I have brushed off the wax?

I'm keen on learning how to repair properly (don't have any power tools but at least would like to know how), is there a good website/video that you can direct me to, please? I've seen basic "off-the-shelf" kit how-to videos but nothing more informational or technical...

Tried again today. Poured the resin into a glass container, mixed well, few strokes with the brush to leave a nice coat. 5min rest prior to putting it outside (cloud). 15min exposure to UV gave a nice shine on the surface but bit tacky still. Massive improvement from last time, but I blame the weather for the marginal tacky-ness.

after 30min out in the UV, sanded with 80 grit initially to get rid of the tacky surface, then 150, 180, up to 400 no problem. Came out nicely. Not perfect, but good enough for my satisfaction.

I think I'll stick with resin + catalysis than UV resin. Though I'm on the sunshine coast, the sun doesn't come out when it's most needed...

Hello Matt, I didn't add any wax. I used the off-the-shelf repair kit with UV curing resin. So I guess it's not technically a hot coat. I wanted to add another coat of resin to fill the bubbles and weaves of cloths. I'm coming to realisation that after all, I wasn't using the right resin for this purpose. Hence the tacky-ness?

I found this website which shows how to make a board in detail. There's a page about hot coat: http://www.surfersteve.com/hotcoat.htm.Here it says add 2% of styrene wax with usual ratio of resin and catalyst. How much do you use matt?

1. Use a rough grip paper the sand back through the resin. The paper will gum up quickly and you will go through alot of it, you may also get dirty smears of resin....its hard going, I have made this mistake once.

2. Add another hotcoat with 2-4% wax in styrene solution mixed in. Brush resin onto board in length way strokes, then brush the resin in width strokes (scraping excess resin off your brush after each stroke), then full length light strokes, first stroke along the stringer and work outwards. Walk away and let it set. This is the method I use for my hot & gloss coats and seems to work.

...go for option 2, board will be heavy as this will be your 2nd or 3rd (?) hotcoat, just go heavier on the sanding but try not to sand through to the cloth.

Because I didn't have any wax at the time, I went for option 1 using P80 (which gummed up like mad) to sand thorugh the tacky resin, then dry P150 and P180, and finally wet P240 and P400. I had the tapes around the area so just simply sanded the ridges and over the area lightly.

The finish looks bit cloudy rather than a shine, but certainly better than leaving with the tacky resin. Very smooth when I run my fingers across the area, only couple of noticeable bumps/catches. Can't really tell where I began the coating. Not perfect, but I'm happy with this finish. Very strong (well for now).

I'm keen on learning how to repair boards. Where would be a good place to source resin, catalyst, styrene wax (are styrene and wax separate compound?)? Seabase? I spend most of my time now in the southeast; I'm not sure if there is a place nearby which repairs boat hulls/sailing equipments. That'll be handy.

The brush technique I mentioned was for hotcoating a full board, obviously not necessary for a repair....i miss read your post slightly.

Wax in Styrene comes in pre-mixed form, you can buy styrene separate so make sure you get the right one.

Seabase and Homeblown are the 2 major surfboard construction suppliers in the UK. East Coast fibreglass are also good.

I would recommend getting a UV stable resin (all of the above provide surfboard specific resin that is UV stable). You can get cheaper poly resin that isn't, it looks clear to begin with but will go yellow/brown after a few trips outside (even if you use white pigment).